Method of manufacturing composite molded body

ABSTRACT

There is provided a method of manufacturing a composite molded body that can increase a processing speed and a joining strength in a different direction. The method of manufacturing a composite molded body in which a metal molded body and a resin molded body are joined, includes the steps of: continuously irradiating a joint surface of the metal molded body with laser light at an irradiation speed of 2,000 mm/sec or more by using a continuous-wave laser; and arranging, within a mold, a portion of the metal molded body including the joint surface irradiated with the laser light in the preceding step and performing injection molding of a resin forming the resin molded body, or performing compression molding in a state where a portion of the metal molded body including the joint surface irradiated with the laser light in the preceding step and a resin forming the resin molded body are made to contact with each other.

This is a divisional of prior U.S. application Ser. No. 14/778,422,which was the national stage of International Application No.PCT/JP2014/057837, filed Mar. 20, 2014.

TECHNICAL FIELD

The present invention relates to a method of manufacturing a compositemolded body formed of a metal molded body and a resin molded body.

BACKGROUND ART

Although resin molded bodies are used as a replacement for metals fromthe viewpoint of reducing the weights of various types of components, itmay often be difficult to replace all metal components with resins. Insuch a case, it can be considered that a new composite component ismanufactured by integrally joining a metal molded body and a resinmolded body.

However, a technology capable of integrally joining a metal molded bodyand a resin molded body in an industrially advantageous manner and witha high joining strength is not commercially available.

JP-B 4020957 discloses a method of performing laser processing on ametal surface for joining different types of materials (resins)including a process of performing laser scanning on the metal surface inone scanning direction and a process of performing laser scanning in ascanning direction that crosses it.

JP-A 2010-167475 discloses a laser processing method of performing laserscanning a plurality of times further in a superimposed manner, in theinvention of JP-B 4020957.

However, since in the inventions disclosed in JP-B 4020957 and JP-A2010-167475, it is necessary to perform laser scanning in two directionscrossing each other without fail, there is room for improvement in thatit takes a long time to perform the processing.

Furthermore, although it is considered that sufficient surfaceroughening processing can be performed by the laser scanning in thecrossing directions to thereby be capable of increasing the joiningstrength, the surface roughness state is not uniform, with the resultthat there exists a problem in which the directivity of the strength ofthe joining part of a metal and a resin may be instable.

For example, there may be generated a problem in which one jointed bodyhas the highest shear force and tensile strength in an X axis direction,but another jointed body has the highest shear force and tensilestrength in a Y axis direction different from the X axis direction, andfurthermore, yet another jointed body has the highest shear force andtensile strength in a Z axis direction different from the X axisdirection and the Y axis direction.

Although there are cases where a composite body of a metal and a resinhaving a high joining strength in a specific direction is requireddepending on products (for example, a rotating body component in onedirection and a reciprocating component in one direction), theabove-described request cannot be sufficiently met in the inventionsdisclosed in JP-B 4020957 and JP-A 2010-167475.

Furthermore, in the case where a joint surface has a complicated shapeor a shape including a thin width part (for example, a star shape, atriangle shape or a dumbbell shape), it can also be considered that asufficient joining strength cannot be obtained as a result of the factthat surface roughening processing is partially non-uniform by themethod of performing laser scanning in the crossing directions.

JP-A 10-294024 discloses a method of manufacturing an electrical andelectronic component in which a concavity and a convexity is formed byirradiating a metal surface with laser light and in which injectionmolding is performed on the concavity and convexity-forming site with aresin, a rubber or the like.

Embodiments 1 to 3 describe that the concavity and convexity is formedby irradiating the surface of a long metal coil with a laser. Then,paragraph [0010] of JP-A 10-294024 describes that the surface of thelong metal coil is roughened so as to be striped or satin-shaped, andparagraph [0019] of JP-A 10-294024 discloses that the surface of thelong metal coil is roughened so as to be striped, dotted, wavy, knurledor satin-shaped.

However, as described in the effects of the invention of paragraphs[0021] and [0022]JP-A 10-294024 , the purpose of the laser irradiationis to form fine and irregular concavities and convexities in the surfaceof the metal to thereby enhance an anchor effect. In particular, sincethe long metal coil is a target to be processed, it is considered thatfine and irregular concavities and convexities are inevitably formedeven when any concavity and convexity are formed.

Therefore, the invention disclosed in JP-A 10-294024 discloses the sametechnical thought as in the invention in which laser irradiation isperformed in the crossing directions to form fine concavities andconvexities in the surface as in the inventions disclosed in JP-B4020957 and JP-A 2010-167475.

WO-A1 2012/090671 discloses a method of manufacturing a composite moldedbody formed of a metal molded body and a resin molded body. The methodincludes a process of performing laser scanning so as to form straightand/or curved markings, on the joint surface of the metal molded body,in one direction or a different direction, and a process of performinglaser scanning such that the straight and/or curved markings do notintersect with each other. In FIGS. 6 to 9, quadrangular, circular, ovaland triangular marking patterns are shown.

SUMMARY OF THE INVENTION

Since in any method of the conventional technology, laser irradiation isperformed in the form of pulse waves (non-continuous waves), theprocessing speed becomes disadvantageously slow.

An object of the present invention is to provide a method ofmanufacturing a composite molded body that can increase the processingspeed and that can increase the joining strength in a differentdirection.

As a means for solving the problem, according to the present invention,there is provided a method of manufacturing a composite molded body inwhich a metal molded body and a resin molded body are joined, the methodincluding the steps of: continuously irradiating a joint surface of themetal molded body with laser light at an irradiation speed of 2,000mm/sec or more by using a continuous-wave laser; and arranging, within amold, a portion of the metal molded body including the joint surfaceirradiated with the laser light in the preceding step and performinginjection molding of a resin forming the resin molded body.

As another means for solving the problem, according to the presentinvention, there is provided a method of manufacturing a compositemolded body in which a metal molded body and a resin molded body arejoined, the method including the steps of: continuously irradiating ajoint surface of the metal molded body with laser light at anirradiation speed of 2,000 mm/sec or more by using a continuous-wavelaser; and arranging, within a mold, a portion of the metal molded bodyincluding the joint surface irradiated with the laser light in thepreceding step and performing compression molding in a state where atleast the joint surface and a resin forming the resin molded body aremade to contact with each other.

According to the method of manufacturing a composite molded body of thepresent invention, the processing speed can be increased, consequently,the processing time can be reduced and furthermore, the joining strengthof a metal molded body and a resin molded body can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view (including a partially enlarged view)of a composite molded body of the present invention in a thicknessdirection;

FIG. 2 is a cross-sectional view of, in a thickness direction, of acomposite molded body of another embodiment of the present invention;

FIG. 3 is an illustrative diagram of a continuous irradiation pattern oflaser light;

FIG. 4 is an illustrative diagram of a continuous irradiation pattern oflaser light in another embodiment;

FIG. 5 is an illustrative diagram of a continuous irradiation pattern oflaser light in yet another embodiment;

FIG. 6 is an illustrative diagram of a continuous irradiation pattern oflaser light in an embodiment;

FIG. 7(a) is a cross-sectional view along line D-D when viewed from anarrow direction shown in FIG. 6, and FIG. 7(b) is a cross-sectional viewof another embodiment along line D-D when viewed from an arrow directionshown in FIG. 6;

FIG. 8(a) is a cross-sectional view along line A-A when viewed from anarrow direction shown in FIG. 6, FIG. 8(b) is a cross-sectional viewalong line B-B when viewed from an arrow direction shown in FIG. 6, andFIG. 8(c) is a cross-sectional view along line C-C when viewed from anarrow direction shown in FIG. 6;

FIG. 9 is an illustrative diagram of a method of manufacturing acomposite molded body when injection molding is performed;

FIG. 10 is a SEM photograph of the surface of a metal molded body afterlaser irradiation is continuously performed in Example 1;

FIG. 11 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 2;

FIG. 12 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 3;

FIG. 13 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 4;

FIG. 14 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 5;

FIG. 15 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 6;

FIG. 16 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in ComparativeExample 2;

FIG. 17 is an illustrative diagram of a method of measuring a shearjoining strength (SI) when pulled in a direction parallel to the jointsurface;

FIG. 18 is an illustrative diagram of a method of manufacturing acomposite molded body when injection molding is performed;

FIG. 19 is a perspective view of the manufactured composite molded body;

FIG. 20 is an illustrative diagram of a method of measuring a tensilejoining strength (S2) of the composite molded body;

FIG. 21 is an illustrative diagram of a method of manufacturing thecomposite molded body when compression molding is performed;

FIG. 22 is a perspective view of the composite molded body manufacturingby the compression molding;

FIG. 23 is an illustrative diagram of a method of measuring the tensilejoining strength (S2) when pulled in a direction perpendicular to thejoint surface;

FIG. 24 is a SEM photograph of a cross-section, in a thicknessdirection, of the composite molded body obtained in Example 10;

FIG. 25 is a SEM photograph of a cross-section, in the thicknessdirection, of the composite molded body obtained in Example 11;

FIG. 26 is a SEM photograph of a cross-section, in the thicknessdirection, of the composite molded body obtained in Example 12;

FIG. 27 is a SEM photograph of a cross-section, in the thicknessdirection, of the composite molded body obtained in Example 15;

FIG. 28 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 16;

FIG. 29 is a SEM photograph of a cross-section, in the thicknessdirection, of the composite molded body obtained in Example 16;

FIG. 30 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 17;

FIG. 31 is a SEM photograph of the joint surface of the metal moldedbody after laser irradiation is continuously performed in Example 21;

FIG. 32 is a graph showing a relationship between an energy density anda groove depth in Test Example 1 and a SEM photograph of a cross-sectionof the composite molded body in the thickness direction; and

FIG. 33 is a graph showing a relationship between an energy density anda groove width in Test Example 1 and a SEM photograph of the jointsurface of the metal molded body after laser irradiation is continuouslyperformed.

DETAILED DESCRIPTION OF THE INVENTION

In a composite molded body 1 obtained by the manufacturing method of thepresent invention, a metal molded body 10 and a resin molded body 20 arejoined on the joint surface 12 of the metal molded body, as shown inFIG. 1.

Hereinafter, the method of manufacturing the composite molded body 1will be described for each process.

In the first process, laser light irradiation is continuously performed,by using a continuous-wave laser, on the joint surface 12 of the metalmolded body 10 at an irradiation speed of 2,000 mm/sec or more.

In this process, the laser light irradiation is continuously performedon the joint surface 12 at a high irradiation speed, and thus it ispossible to roughen the joint surface 12 in a very short period of time.In the joint surface 12 of FIG. 1 (partially enlarged view), the stateof the roughened surface is illustrated in an exaggerated manner.

The irradiation speed of the continuous-wave laser is preferably 2,000to 20,000 mm/sec, more preferably 2,000 to 18,000 mm/sec, and furtherpreferably 2,000 to 15,000 mm/sec.

The irradiation speed of the continuous-wave laser falls within theabove range, and thus it is possible to increase the processing speed(that is, it is possible to reduce the processing time), with the resultthat it is also possible to maintain the joint surface at a high level.

In this process, preferably, the laser light irradiation is continuouslyperformed such that the processing time is in a range of 0.1 to 30seconds when the following requirements (A) and (B) are satisfied:

(A) The irradiation speed of the laser light is 2,000 to 15,000 mm/sec.

(B) The area of the joint surface of the metal molded body is 100 mm².

In the case where the processing time when the requirements (A) and (B)are satisfied is made to fall within the above range, it is possible toroughen (perform roughening on) the entire joint surface 12.

Although, for example, the following method can be applied to thecontinuous irradiation with the laser light, the method is notparticularly limited as long as a method capable of roughening the jointsurface 12 is adopted.

(I) A method of performing the continuous irradiation such that, asshown in FIGS. 3 and 4, one straight line or curved line is formed fromthe side of one-side (a short side or a long side) of the joint surface(for example, a rectangle) 12 toward the side on the opposite side, andof repeating this to thereby form a plurality of straight lines orcurved lines,

(II) A method of performing the continuous irradiation such that astraight line or a curved line is continuously formed from the side ofone-side of the joint surface toward the side on the opposite side, andthen, of repeating the continuous irradiation such that straight linesor curved lines are formed at intervals in the opposite direction,

(III) A method of performing the continuous irradiation from the side ofone-side of the joint surface toward the side on the opposite side, andthen, performing the continuous irradiation in a direction perpendicularthereto,

(IV) A method of randomly performing the continuous irradiation on thejoint surface.

When the methods of (I) to (IV) are performed, one straight line or onecurved line can also be formed by performing the continuous irradiationwith the laser light a plurality of times.

Under the same conditions of the continuous irradiation, as the numberof times (repetition times) of irradiation for forming one straight lineor one curved line is increased, the degree to which the joint surface12 is roughened becomes larger.

When, in the methods of (I) and (II), a plurality of straight lines or aplurality of curved lines is formed, it is possible to performcontinuous irradiation with the laser light such that the respectivestraight lines or the respective curved lines are formed at equalintervals in the range of 0.005 to 1 mm (the intervals of b1 shown inFIG. 3).

The interval at this time is set larger than the beam diameter (spotdiameter) of the laser light, and the number of straight lines or curvedlines at this time can be adjusted in response to the area of the jointsurface of the metal molded body 10.

When, in the methods of (I) and (II), a plurality of straight lines or aplurality of curved lines is formed, it is possible to performcontinuous irradiation with the laser light such that the respectivestraight lines or the respective curved lines are formed at equalintervals in the range of 0.005 to 1 mm (the intervals of b1 shown FIGS.3 and 4).

Then, the plurality of straight lines or the plurality of curved linesis assumed to be one group, and it is possible to form a plurality ofgroups.

The interval between the respective groups at this time can be set atequal intervals in the range of 0.01 to 1 mm (the interval of b2 shownin FIG. 4).

Note that, instead of the continuous irradiation method shown in FIGS. 3and 4, as shown in FIG. 5, a method of performing the continuousirradiation without interruption can also be carried out during the timefrom the start of the continuous irradiation to the completion of thecontinuous irradiation.

For example, the continuous irradiation with the laser light can beperformed under the following conditions.

The output is preferably 4 to 4000 W, more preferably 50 to 2500 W,further preferably 100 to 2,000 W and further more preferably 250 to2,000 W.

The beam diameter (spot diameter) is preferably 5 to 200 μm, morepreferably 5 to 100 μm, further preferably 10 to 100 μm and further morepreferably 11 to 80 μm.

Moreover, a preferable range of a combination of the output and the spotdiameter can be selected from an energy density (W/μm²) determined fromthe laser output and a laser irradiation spot area (n×[spotdiameter/2]²).

The energy density (W/μm²) is preferably 0.1 W/μm² or more, morepreferably 0.2 to 10 W/μm² and further preferably 0.2 to 6.0 W/μm².

When the energy density (W/μm²) is the same and the output (W) ishigher, a larger spot area (μm²) can be irradiated with the laser, andthus the processing speed (the laser irradiation area per second:mm²/sec) is increased, with the result that the processing time can beshortened.

The wavelength is preferably 300 to 1200 nm, more preferably 500 to 1200nm.

The focus position is preferably −10 to +10 mm, more preferably −6 to +6mm.

A preferable relationship among the irradiation speed of thecontinuous-wave laser, the laser output, the laser beam diameter (spotdiameter) and the energy density is that the irradiation speed of thecontinuous-wave laser is 2,000 to 15,000 mm/sec, the laser output is 250to 2,000 W, the laser beam diameter (spot diameter) is 10 to 100 μm andthe energy density (W/μm²) determined from the laser output and the spotarea (n×[spot diameter/2]²) is 0.2 to 10 W/μm².

The metal of the metal molded body 10 is not particularly limited, andcan be appropriately selected from known metals according to theintended use. Examples thereof can include one selected from: iron,various types of stainless steels, aluminum and alloys thereof, andcopper, magnesium and alloys containing them.

The joint surface 12 of the metal molded body 10 may be a flat surfaceas shown in FIG. 1, may be a curved surface as shown in FIG. 2 or mayhave both a flat surface and a curved surface.

A known continuous-wave laser can be used as the continuous-wave laser.Examples that can be used include: a YVO₄ laser, a fiber laser, anexcimer laser, a carbon dioxide laser, an ultraviolet laser, a YAGlaser, a semiconductor laser, a glass laser, a ruby laser, a He—Nelaser, a nitrogen laser, a chelate laser and a dye laser.

In the method of manufacturing the composite molded body according tothe present invention, the joint surface 12 of the metal molded body iscontinuously irradiated with laser light by using the continuous-wavelaser at an irradiation speed of 2,000 mm/sec or more, and thus the partcontinuously irradiated with the laser light is roughened.

At this time, one embodiment of a state of the joint surface 12 of themetal molded body at this time will be described with reference to FIGS.6 to 8.

As shown in FIG. 6, irradiation with the laser light (for example, thespot diameter of 11 μm) is continuously performed to form a large numberof lines (in the figure, three lines 61 to 63 are shown; the distancetherebetween is approximately 50 μm), with the result that roughening ispossible. The number of times one straight line is irradiated ispreferably 1 to 10.

At this time, the surface-layer part of the metal molded body 10including the roughened joint surface 12 here is shown in FIG. 7(a) andFIGS. 8(a) to 8(c). Note that the “surface-layer part of the metalmolded body 10” refers to a portion from the surface to about the depthof an open hole (stem hole or branch hole) formed by the roughening.

Note that, although when the number of times one straight line isirradiated exceeds 10, it is possible to further increase the level ofroughening and to enhance, in the composite molded body 1, the joiningstrength of the metal molded body 10 and the resin molded body 20, thetotal application time is increased. Accordingly, in consideration of arelationship between the joining strength of the composite molded body 1and the manufacturing time intended, it is preferable to determine thenumber of times one straight line is irradiated. When the number oftimes one straight line is irradiated exceeds 10, the number of timespreferably is 50 or less, is more preferably 15 to 40 and is furtherpreferably 20 to 35.

As shown in FIGS. 7 and 8, the surface-layer part of the metal moldedbody 10 including the roughened joint surface 12 includes an open hole30 having an open portion 31 on the side of the joint surface 12.

The open hole 30 is formed of a stem hole 32 having the open portion 31formed in a thickness direction and a branch hole 33 formed from theinner wall surface of the stem hole 32, in a direction different fromthe stem hole 32. One or a plurality of branch holes 33 may be formed.

Note that, as long as the joining strength of the metal molded body 10and the resin molded body 20 can be maintained in the composite moldedbody 1, a part of the open hole 30 may be formed of only the stem hole32 and may be without the branch hole 33.

As shown in FIGS. 7 and 8, the surface-layer part of the metal moldedbody 10 including the roughened joint surface 12 includes an inner space40 without the open portion on the side of the joint surface 12.

The inner space 40 is connected to the open hole 30 through a tunnelconnection path 50.

As shown in FIG. 7(b), the surface-layer part of the metal molded body10 including the roughened joint surface 12 may include an open space 45in which a plurality of open holes 30 is formed into one, and the openspace 45 may be formed by combining the open hole 30 and the inner space40 into one. One open space 45 has an internal volume larger than oneopen hole 30.

Note that the open space 45 in the shape of a groove may be formed byuniting a large number of open holes 30 into one.

Although not illustrated, two inner spaces 40 as shown in FIG. 8(a) maybe connected to each other through the tunnel connection path 50, or theopen space 45, the open hole 30, the inner space 40 and other openspaces 45 as shown in FIG. 7(b) may be connected through the tunnelconnection path 50.

Although all the inner spaces 40 are connected to one or both of theopen hole 30 and the open space 45 through the tunnel connection path50, a part of the inner spaces 40 may be a space in a closed state ofnot being connected to the open hole 30 and the open space 45 as long asthe joining strength of the metal molded body 10 and the resin moldedbody 20 can be maintained in the composite molded body 1.

Although the details of how the open hole 30, the inner space 40 and thelike as shown in FIGS. 7 and 8 are formed when the laser lightirradiation is continuously performed as described above are not clear,it can be considered that, when the laser light irradiation iscontinuously performed at a predetermined speed or more, a hole and agroove are temporarily formed in the surface of the metal molded body,but the hole and the groove are raised and covered by the melted metaland are blocked, with the result that the open hole 30, the inner space40 and the open space 45 are formed.

Furthermore, in the same way, although the details of how the branchhole 33 of the open hole 30 and the tunnel connection path 50 are formedare not clear, it is considered that the side wall parts of the hole andthe groove are melted by heat staying near the bottom portion of thehole and the groove temporarily formed, with the result that the branchhole 33 was formed by melting the inner wall of the stem hole 32, andfurthermore, the tunnel connection path 50 is formed by extension of thebranch hole 33.

Note that, when a pulse laser is used instead of the continuous-wavelaser, in the joint surface of the metal molded body, the open hole andthe groove are formed, but the inner space having no open portion andthe connection path connecting the open hole and the inner space are notformed.

In the subsequent process, a portion of the metal molded body 10including the roughened joint surface 12, and the resin molded body 20are integrated.

In this process, any one of the following methods can be applied: aprocess of arranging, within a mold, a portion of the metal molded bodyincluding the joint surface irradiated with the laser light in thepreceding process and performing injection molding of a resin formingthe resin molded body; and a process of arranging, within a mold, aportion of the metal molded body including the joint surface irradiatedwith the laser light in the preceding step and performing compressionmolding in a state where at least the joint surface and a resin formingthe resin molded body are made to contact with each other.

In addition, a known molding method which is used as a method of moldinga thermoplastic resin or a thermosetting resin can be applied.

When a thermoplastic resin is used, there may be adopted a method inwhich the resin is allowed to enter the hole, the groove and the tunnelconnection path formed in the metal molded body, by applying a pressureor the like to the molten resin and thereafter the composite molded bodyis obtained by cooling and solidifying the resin. A molding method suchas injection compression molding can also be used in addition toinjection molding and compression molding.

When a thermoplastic resin is used, there may be adopted a method inwhich the resin is allowed to enter the hole, the groove and the tunnelconnection path formed in the metal molded body, by applying a pressureor the like to the resin in a liquid or molten state, and thereafter thecomposite molded body is obtained by heat-curing the resin. A moldingmethod such as transfer molding can also be used in addition toinjection molding and compression molding.

When a compression molding method is applied, there can be applied, forexample, a method in which the metal molded body 10 is arranged in astate where the joint surface 12 is exposed to the interior of a moldframe (in a state where the joint surface is on the surface side), athermoplastic resin, a thermoplastic elastomer or a thermosetting resin(however, a pre-polymer) is put into the mold frame and thereaftercompression is performed.

Note that, when in an injection molding method or a compression moldingmethod, a thermosetting resin (a pre-polymer) is used, thermosetting isperformed by heating or the like in the subsequent process.

The resin of the resin molded body used in this process includes notonly a thermoplastic resin and a thermosetting resin but also athermoplastic elastomer.

The thermoplastic resin can be appropriately selected as necessary fromknown thermoplastic resins according to the intended use. Examplesthereof can include a polyamide-based resin (an aliphatic polyamide suchas PA6 and PA66 or an aromatic polyamide), a copolymer containingpolystyrene units such as polystyrene, ABS resin and AS resin, acopolymer containing polyethylene and ethylene units, a copolymercontaining polypropylene and propylene units, other polyolefins,polyvinyl chloride, polyvinylidene chloride, a polycarbonate-basedresin, an acrylic resin, a methacrylic-based resin, a polyester-basedresin, a polyacetal-based resin and a polyphenylene sulfide-based resin.

The thermosetting resin can be appropriately selected as necessary fromknown thermosetting resins according to the intended use. Examplesthereof can include a urea resin, a melamine resin, a phenol resin, aresorcinol resin, an epoxy resin, polyurethane and vinyl urethane.

The thermoplastic elastomer can be appropriately selected as necessaryfrom known thermoplastic elastomers according to the intended use.Examples thereof can include a styrene-based elastomer, a vinylchloride-based elastomer, an olefin-based elastomer, a urethane-basedelastomer, a polyester-based elastomer, a nitrile-based elastomer and apolyamide-based elastomer.

It is possible to blend known fibrous fillers with these thermoplasticresins, heat-curable resins and thermoplastic elastomers.

The known fibrous fillers can include a carbon fiber, an inorganicfiber, a metal fiber and an organic fiber.

The carbon fiber is the well-known fibrous filler, and PAN-based,pitch-based, rayon-based and lignin-based fibers can be used.

The inorganic fibers can include a glass fiber, a basalt fiber, a silicafiber, a silica-alumina fiber, a zirconia fiber, a boron nitride fiber,a silicon nitride fiber and the like.

The metal fibers can include fibers formed of stainless steel, aluminum,copper and the like.

Examples of the organic fibers that can be used include: syntheticfibers such as a polyamide fiber (a wholly aromatic polyamide fiber, ora semi-aromatic polyamide fiber in which either a diamine or adicarboxylic acid is an aromatic compound and an aliphatic polyamidefiber), a polyvinyl alcohol fiber, an acrylic fiber, a polyolefin fiber,a polyoxymethylene fiber, a polytetrafluoroethylene fiber, a polyesterfiber (including a wholly aromatic polyester fiber), a polyphenylenesulfide fiber, a polyimide fiber and a liquid crystalline polyesterfiber; natural fibers (such as cellulose-based fibers); a regeneratedcellulose (rayon) fiber; and the like.

Although the fibrous fillers having a fiber diameter within a range of 3to 60 μm can be used, among them, for example, a fibrous filler having afiber diameter smaller than the diameter of the opening of the open hole30 or the like formed by roughening the joint surface 12 of the metalmolded body 10 is preferably used. The fiber diameter is more preferably5 to 30 μm and is further preferably 7 to 20 μm.

The above-described fibrous filler whose fiber diameter is smaller thanthe diameter of the opening of the open hole 30 is preferably usedbecause when it is used, the composite molded body in which part of thefibrous filler tensionally enters the open hole 30 or the like of themetal molded body is obtained to increase the joining strength of themetal molded body and the resin molded body.

The blending amount of a fibrous filler relative to 100 mass parts ofthe thermoplastic resin, the thermosetting resin or the thermoplasticelastomer is preferably 5 to 250 mass parts. The blending amount is morepreferably 25 to 200 mass parts, and is further preferably 45 to 150mass parts.

The composite molded body 1 obtained by the manufacturing method of thepresent invention is integrated in a state where the resin forming theresin molded body 20 enters into the open hole 30 of the metal moldedbody 10 as shown in FIGS. 7 and 8, the inner space 40, the tunnelconnection path 50 and the open space 45.

The resin enters the inside of the open hole 30 (the stem hole 32 andthe branch hole 33) and the open space 45 through the opening partsthereof, and the resin entering through the opening portions of the openhole 30 and the open space 45 enters the inside of the inner space 40through the tunnel connection path 50.

Accordingly, in the composite molded body 1 obtained by themanufacturing method of the present invention, both a shear joiningstrength (S1) when the resin molded body 20 is pulled in a paralleldirection (the X direction of FIG. 1) in a state where, in FIG. 1, anend portion of the metal molded body 10 is fixed to the joint surface 12of the metal molded body 10 and the resin molded body 20, and a tensilejoining strength (S2) when the resin molded body 20 is pulled in adirection (the Y direction of FIG. 1) perpendicular to the joint surface12 of the metal molded body 10 and the resin molded body 20 areincreased as compared with the composite molded body in which the resinenters into only the open hole 30 and the open space 45.

EXAMPLES Examples 1 to 6 and Comparative Examples 1 to 3

In the Examples and Comparative Examples, the entire surface (an areasize of 40 mm²) of the joint surface 12 of a metal molded body(aluminum: A5052) shown in FIG. 9 was continuously irradiated with laserlight under the conditions shown in Table 1.

In Examples 1 to 5 and Comparative Examples 1 to 3, as shown in FIG. 3,the laser light irradiation was continuously performed, and in Example6, as shown in FIG. 4, the laser light irradiation was continuouslyperformed.

Then, injection molding was performed by the following method throughthe use of the processed metal molded body, and a composite molded bodyshown in FIG. 17 in the Examples and Comparative Examples was obtained.

FIG. 10 a SEM photograph (a magnification of 100, a magnification of500, a magnification of 700 and a magnification of 2500) of the jointsurface of the metal molded body after the continuous irradiation with acontinuous-wave laser in Example 1. It was able to be confirmed that thejoint surface was roughened and that small concave portions were formed.

FIG. 11 a SEM photograph (a magnification of 100 and a magnification of500) of the joint surface of the metal molded body after the continuousirradiation with the continuous-wave laser in Example 2. It was able tobe confirmed that the joint surface was roughened and that small concaveportions were formed.

FIG. 12 a SEM photograph (a magnification of 100 and a magnification of500) of the joint surface of the metal molded body after the continuousirradiation with the continuous-wave laser in Example 3. It was able tobe confirmed that the joint surface was roughened and that small concaveportions were formed.

FIG. 13 a SEM photograph (a magnification of 100 and a magnification of500) of the joint surface of the metal molded body after the continuousirradiation with the continuous-wave laser in Example 4. It was able tobe confirmed that the joint surface was roughened and that small concaveportions were formed.

FIG. 14 a SEM photograph (a magnification of 100 and a magnification of500) of the joint surface of the metal molded body after the continuousirradiation with the continuous-wave laser in Example 5. It was able tobe confirmed that the joint surface was roughened and that small concaveportions were formed.

FIG. 15 a SEM photograph (a magnification of 100 and a magnification of500) of the joint surface of the metal molded body after the continuousirradiation with the continuous-wave laser in Example 6. It wasconfirmed that the joint surface was roughened and that small concaveportions were formed.

FIG. 16 a SEM photograph (a magnification of 100 and a magnification of500) of the joint surface of the metal molded body after the continuousirradiation with the continuous-wave laser in Comparative Example 2.Since the irradiation speed was 1000 mm/sec, the joint surface was notsufficiently roughened.

<Injection Molding>

Resin: GF60% reinforced PA66 resin (PLASTRON PA66-GF60-01 (L7):manufactured by Daicel Polymer Co., Ltd.), the fiber length of the glassfiber: 11 mm

Rein temperature: 320° C.

Mold temperature: 100° C.

Injection molding machine: ROBOSHOT S2000i100B manufactured by FANUCCorporation

Tensile Test

The composite molded body shown in FIG. 17 in Examples and ComparativeExamples was used, and the shear joining strength (S1) was evaluated byperforming a tensile test. The results thereof are shown in Table 1.

In the tensile test, in a state where the end portion on the side of themetal molded body 10 was fixed, when the composite molded body waspulled in the X direction (the X direction of FIG. 1, the directionparallel to the joint surface 12) shown in FIG. 17 until the metalmolded body 10 and the resin molded body 20 were broken, there wasmeasured the maximum load until the joint surface 12 was broken.

<Tensile Test Conditions>

Test machine: Tensilon (UCT-1T) manufactured by Orientec Co., Ltd

Tensile speed: 5 mm/min

Distance between chucks: 50 mm

TABLE 1 Compar- Compar- Compar- Example Example Example Example ExampleExample ative ative ative 1 2 3 4 5 6 Example 1 Example 2 Example 3 Typeof metal Al AI Type of resin PA66(including GF) PA66 (including GF)Joining method Injection molding Injection molding Laser oscillatorFiber laser YVO₄ laser Fiber laser Waveform Contin- Contin- Contin-Contin- Contin- Contin- Pulse Contin- Contin- uous uous uous uous uousuous wave uous uous wave wave wave wave wave wave wave wave Output(W)274 274 274 274 274 274 6 274 274 Wavelength (nm) 1070 1070 1070 10701070 1070 1064 1070 1070 Pulse width (nsec) — — — — — — 30 — — Frequency(kHz) — — — — — — 50 — — Spot diameter 11 11 11 11 11 11 30 11 11 (μm)[Energy density 2.8 2.8 2.8 2.8 2.8 2.8 0.0085 2.8 2.8 (W/μm²) Laserirradiation speed 10000 10000 10000 13333 13333 13333 500 1000 100(mm/sec) Number of lines 80 80 80 80 40 99 500 80 80 Line distance (b1)(mm) 0.05 0.05 0.05 0.05 0.1 0.03 0.008 0.05 0.05 Line group distance —— — — — 0.06 — — • • (b2) (mm) Number of times of 1 3 10 1 1 3 1 1 1repetition (times) Processing area 40 40 40 40 40 40 40 40 40 (mm²)Processing time(s) 0.4 1 3 0.3 0.2 1.3 20 4 40 Shear joining 5 18 25 812 29 3 0 0 strength (MPa)

As can be confirmed from comparison between Example 1 and ComparativeExample 1, in Example 1, the composite molded body having a higherjoining strength was obtained in fiftieth of the processing time.

In consideration of mass production on an industrial scale, theindustrial value of the manufacturing method in Example 1 of being ableto reduce the processing time (namely, being able to reduce the energyrequired for manufacturing) is very high.

As can be confirmed from a comparison between Example 1 and Examples 2and 3, as in Examples 2 and 3, the number of times the laser irradiationwas repeated was increased, and thus the joining strength was able to beincreased, with the result that, even in this case, the processing timewas able to be reduced as compared with Comparative Examples 1 to 3.

As can be confirmed from a comparison between Examples 1 to 3 andExamples 4 to 6, when the laser irradiation speed was increased as inExamples 4 to 6, the shear joining strength (S1) (the joining strengthin the X direction of FIGS. 1 and 17) was able to be increased.

Examples 7 to 9 and Comparative Examples 4 to 6

In the Examples and Comparative Examples, the entire surface (an areasize of 90 mm²) of the joint surface 12 of a metal molded body(aluminum: A5052) shown in FIG. 18 was continuously irradiated withlaser light under the conditions shown in Table 2.

Thereafter, the composite molded body shown in FIG. 19 was obtained inthe same way as in Examples 1 to 6 and Comparative Examples 1 to 3.

As to the obtained composite molded body, the tensile joining strength(S2) corresponding to the Y direction (the Y direction of FIG. 20) shownin FIG. 1 was measured by the following method.

In the tensile test, as shown in FIG. 20, in a state where the side ofthe metal molded body 10 was fixed by a jig 70, when the compositemolded body was pulled in the Y direction (the Y direction of FIG. 1,the vertical direction with respect to the joint surface 12) shown inFIG. 20 until the metal molded body 10 and the resin molded body 20 werebroken, there was measured the maximum load until the joint surface 12was broken.

<Tensile Test Conditions>

Test machine: Tensilon (UCT-1T) manufactured by Orientec Co., Ltd

Tensile speed: 5 mm/min

Distance between chucks: 50 mm

TABLE 2 Example Example Example Comparative Comparative Comparative 7 89 Example 4 Example 5 Example 6 Type of metal Al Al Type of resin PA66(including GF) PA66 (including GF) Joining method Injection moldingInjection molding Laser oscillator Fiber laser YV0₄ laser Fiber laserWaveform Continuous Continuous Continuous Pulse Continuous Continuouswave wave wave wave wave wave Output (W) 274 274 274 6 274 274Wavelength (nm) 1070 1070 1070 1064 1070 1070 Pulse width (nsec) — — —30 — — Frequency (kHz) — — — 50 — — Spot diameter (μm) 11 11 11 30 11 11Energy density 2.8 2.8 2.8 2.8 2.8 2.8 (W/μm²) Laser irradiation 1000010000 10000 500 1000 100 speed (mm/sec) Number of lines 120 120 120 750120 120 Line distance (b1) (mm) 0.05 0.05 0.05 0.008 0.05 0.05 Linegroup distance — — — — — — (b2) (mm) Number of times of 1 3 10 1 1 1repetition (times) Processing area (mm²) 90 90 90 90 90 90 Processingtime (s) 0.6 1.6 3 30 6 60 Tensile joining 4 14 21 0 0 0 strength (MPa)

Although Examples 7 to 9 (the area of the joint surface 12: 90 mm²) inTable 2 correspond to Examples 1 to 3 (the area of the joint surface 12:40 mm²) in Table 1, the area of the joint surface 12 is 2.25 times thatthereof.

However, as is clear from a comparison with Comparative Examples 4 to 6in Table 2, it was able to be confirmed that the tensile joiningstrength (S2) when being pulled in a direction (the Y direction ofFIG. 1) perpendicular to the joint surface 12 (the area of 90 mm²) ofthe metal molded body 10 and the resin molded body 20 was also able tobe increased by applying the manufacturing method of the presentinvention.

Examples 10 to 15 and Comparative Examples 7 to 9

In the Examples and Comparative Examples, the entire surface (an areasize of 40 mm²) of the joint surface 12 of a metal molded body(aluminum: A5052) shown in FIG. 21 was continuously irradiated withlaser light under the conditions shown in Table 3.

In Examples 10 to 14 and Comparative Examples 8 and 9, as shown in FIG.3, the laser light irradiation was continuously performed, in Example15, as shown in FIG. 4, the laser light irradiation was continuouslyperformed and in Comparative Example 7, as shown in FIG. 5, the laserlight irradiation was continuously performed.

Then, compression molding was performed by the following method throughthe use of the processed metal molded body, and a composite molded bodyin the Examples and Comparative Examples was obtained.

<Compression Molding>

The metal molded body 10 was arranged within the mold frame (made ofTeflon) so that the joint surface 12 faces upward, and a resin pelletwas added onto the joint surface 12. Thereafter, the mold frame wassandwiched by an iron plate and was compressed under the followingconditions, and thus a composite molded body shown in FIG. 22 wasobtained.

Resin pellet: PA66 resin (2015B manufactured by Ube Industries, Ltd.)

Temperature: 28 5° C.

Pressure: 1 MPa (at the time of preheating), 10 Mpa

Time: 2 minutes (at the time of preheating), 3 minutes

Molding machine: Toyo Seiki Seisakusho Ltd. compressor (mini testpress-10)

Tensile Test

The tensile joining strength (S2) was evaluated through the use of thecomposite molded bodies in Examples and Comparative Examples and byperforming a tensile test. The results thereof are shown in Table 3.

The tensile test was performed as follows.

As shown in FIG. 23, a jig 74 a formed of an aluminum plate 72 a and atensile portion 73 a fixed in a direction perpendicular to the surfacethereof was caused to adhere, with an adhesive 71 a, to the exposedsurface of the resin molded body 20 of the composite molded body.

In the same way, as shown in FIG. 23, a jig 74 b formed of an aluminumplate 72 b and a fixing portion 73 b fixed in a direction perpendicularto the surface thereof was caused to adhere, with an adhesive 71 b, tothe exposed surface of the metal molded body 10 of the composite moldedbody.

In a state where the fixing portion 73 b is fixed, there was measuredthe maximum load when the tensile portion 73 a was pulled under thefollowing conditions until the joint surface 12 was broken.

<Tensile Test Conditions>

Test machine: Tensilon

Tensile speed: 5 mm/min

Distance between chucks: 16 mm

Method of observing inner space

The presence or absence of an inner space having no opening portion waschecked. The method thereof will be described below.

In a joint portion of the composite molded body including the jointsurface 12, three parts were randomly cut in a perpendicular direction(A-A, B-B and C-C directions in FIG. 6) of the laser irradiation, andthe cross-sections of the surface parts thereof were randomly observedat three points, with a scanning electron microscope (SEM).

When the presence or absence of an inner space was able to be checkedwith a SEM observation photograph (magnification of 500), the number ofinner spaces was counted. Note that inner spaces having a maximumdiameter of 10 μm or less were omitted.

The number of inner spaces (the average value of those at 9 places) wasshown (Table 3).

Furthermore, the inner space was analyzed by minute portion X rayanalysis (EDX), and it was confirmed that the resin penetrated the innerspace.

SEM: S-3400N manufactured by Hitachi High-Technologies Corporation

EDX analysis device: Apollo XP manufactured by AMETEK (formerly EDAXJapan) Co., Ltd.

Moreover, when, as shown in FIG. 2, the metal surface of the compositemolded body is a curved surface, the same measurement can be performedby cutting the sample in a direction perpendicular to a tangent of thecurved surface.

Note that, even by using a microscopic laser Raman spectrometer, it canbe confirmed that the resin penetrates the inner space.

TABLE 3 Compar- Compar- Compar- Example Example Example Example ExampleExample ative ative ative 10 11 12 13 14 15 Example 7 Example 8 Example9 Type of metal Al Al Type of resin PA66 PA66 Joining method Compressionmolding Compression molding Laser oscillator Fiber laser Fiber laserWaveform Continuous Continuous Continuous Continuous ContinuousContinuous Pulse Continuous Continuous wave wave wave wave wave wavewave wave wave Output (W) 274 274 274 274 274 274 30 274 274 Wavelength(nm) 1070 1070 1070 1070 1070 1070 1070 1070 1070 Pulse width (nsec) — —— — — — 50 — — Frequency (kHz) — — — — — — 30 — — Spot diameter (μm) 1111 11 11 11 11 45 11 11 Energy density 2.8 2.8 2.8 2.8 2.8 2.8 0.019 2.82.8 (W/μm²) Laser irradiation 10000 10000 10000 13333 13333 13333 5001000 100 speed (mm/sec) Number of lines 80 80 80 80 40 99 60 80 80 Linedistance 0.05 0.05 0.05 0.05 0.1 0.03 0.06 0.05 0.05 (b1) (mm) Linedistance — — — — — 0.06 0.09 — — (b2) (mm) Number of times of 1 3 10 1 13 1 1 1 repetition (times) Processing area (mm²) 40 40 40 40 40 40 40 4040 Processing time(s) 0.4 1 3 0.3 0.2 1.3 1.2 4 40 Inner space (pieces)5 7 6 3 2 3 0 0 0 Tensile joining 19 21 28 18 16 22 1 0 0 strength (MPa)

Since in Examples 10 to 15, the joint surface 12 of the metal moldedbody 10 was continuously irradiated with laser light in the same way asin Examples 1 to 6, the surface of the joint surface 12 of the metalmolded body 10 had the same SEM photographs (FIGS. 10 to 15) shown inExamples 1 to 6.

FIG. 24 is a SEM photograph of a cross-section, in a thicknessdirection, the composite molded body in Example 10 (the cross-sectionalviews of A to C in FIG. 6).

A portion relatively appearing white was the metal molded body 10, and aportion relatively appearing black was the resin molded body 20.

A plurality of holes formed in the thickness direction, and a pluralityof independent spaces were able to be confirmed from FIG. 24, and all ofthem appeared black, and thus it was able to be confirmed that the resinpenetrated.

It was confirmed that the holes formed in the thickness direction wereholes that correspond to the stem holes 32 of the open holes 30.

It was confirmed that the independent spaces are either thecross-sections of the branch holes 33 extended from the inner wallsurface of the stem holes 32 in a direction different from the directionof formation of the stem holes 32, or the inner spaces 40.

Then, when the independent spaces were set to be the inner space 40, itis considered that, since the resin penetrated the interior, the innerspaces 40 are connected by the open hole 30 and the tunnel connectionpath 50.

Accordingly, the tensile joining strength (S2) when the composite moldedbody of Example 10 was pulled in a direction perpendicular to the jointsurface 12 (the Y direction of FIG. 1) was increased.

FIG. 25 is a SEM photograph of a cross-section, in a thicknessdirection, the composite molded body in Example 11 (the cross-sectionalviews of A to C in FIG. 6).

A portion relatively appearing white was the metal molded body 10, and aportion relatively appearing black was the resin molded body 20.

A plurality of holes formed in the thickness direction, and a pluralityof independent spaces were able to be confirmed from FIG. 25, and all ofthem appeared black, and thus it was able to be confirmed that the resinpenetrated.

It was confirmed that the holes formed in the thickness direction wereholes that correspond to the stem holes 32 of the open holes 30.

It was confirmed that the independent spaces are either thecross-sections of the branch holes 33 extended from the inner wallsurface of the stem holes 32 in a direction different from the directionof formation of the stem holes 32, or the inner spaces 40.

Then, when the independent spaces were set to be the inner space 40, itis considered that, since the resin penetrated the interior, the innerspaces 40 are connected by the open hole 30 and the tunnel connectionpath 50.

Accordingly, the tensile joining strength (S2) when the composite moldedbody of Example 11 was pulled in a direction perpendicular to the jointsurface 12 (the Y direction of FIG. 1) was increased.

FIG. 26 is a SEM photograph of a cross-section, in a thicknessdirection, the composite molded body in Example 12 (the cross-sectionalviews of A to C in FIG. 6).

A plurality of holes formed in the thickness direction, and a pluralityof independent spaces were able to be confirmed from FIG. 26, and all ofthem appeared black, and thus it was able to be confirmed that the resinpenetrated.

It was confirmed that the holes formed in the thickness direction wereholes that correspond to the stem holes 32 of the open holes 30.

It was confirmed that the independent spaces are either thecross-sections of the branch holes 33 extended from the inner wallsurface of the stem holes 32 in a direction different from the directionof formation of the stem holes 32, or the inner spaces 40.

Then, when the independent spaces were set to be the inner space 40, itis considered that, since the resin penetrates the interior, the innerspaces 40 are connected by the open hole 30 and the tunnel connectionpath 50.

Accordingly, the tensile joining strength (S2) when the composite moldedbody of Example 12 was pulled in a direction perpendicular to the jointsurface 12 (the Y direction of FIG. 1) was increased.

FIG. 27 is a SEM photograph of a cross-section, in a thicknessdirection, of the composite molded body in Example 15.

A part relatively appearing white was the metal molded body 10, and apart relatively appearing black was the resin molded body 20.

It was able to be confirmed that in the metal molded body 10, a largenumber of open holes 30 were formed.

Therefore, there was increased the tensile joining strength (S2) whenthe composite molded body of Example 15 was pulled in a directionperpendicular to the joint surface 12 (the Y direction of FIG. 1).

Examples 16 to 18

In the same way as in Examples 7 to 9 (Table 2), the entire surface (anarea size of 90 mm²) of the joint surface 12 of a metal molded body (themetal shown in Table 4) shown in FIG. 18 was continuously irradiatedwith laser light under the conditions shown in Table 4.

Thereafter, the composite molded body shown in FIG. 19 was obtained inthe same way as in Examples 1 to 6 and Comparative Examples 1 to 3.

As to the obtained composite molded body, the tensile joining strength(S2) corresponding to the Y direction (the Y direction of FIG. 20) shownin FIG. 1 was measured by the following method.

In the tensile test, as shown in FIG. 20, in a state where the side ofthe metal molded body 10 was fixed by a jig 70, when the compositemolded body was pulled in the Y direction (the Y direction of FIG. 1,the vertical direction with respect to the joint surface 12) shown inFIG. 20 until the metal molded body 10 and the resin molded body 20 werebroken, there was measured the maximum load until the joint surface 12was broken.

<Tensile Test Conditions>

Test machine: Tensilon (UCT-1T) manufactured by Orientec Co., Ltd

Tensile speed: 5 mm/min

Distance between chucks: 50 mm

Examples 19 to 21

The entire surface (an area size of 40 mm²) of the joint surface 12 of ametal molded body (the metal shown in Table 4) shown in FIG. 21 wascontinuously irradiated with laser light under conditions shown in Table4.

The laser light irradiation was continuously performed as shown in FIG.3. Then, compression molding was performed in the same way as inExamples 10 to 15, through the use of the processed metal molded body,and a composite molded body was obtained.

The tensile test and the method of observing the inner space wereperformed in the same way as in Examples 10 to 15.

TABLE 4 Example Example Example Example Example Example 16 17 18 19 2021 Type of metal Al SUS304 Al SUS304 Type of resin PA66 PP PA66(Including GF) (Including GF) Joining method Injection moldingCompression molding Laser oscillator Fiber laser Waveform ContinuousContinuous Continuous Continuous Continuous Continuous wave wave wavewave wave wave Output (W) 274 274 274 274 274 274 Wavelength (nm) 10701070 1070 1070 1070 1070 Pulse width (nsec) — — — — — — Frequency (kHz)— — — — — — Spot diameter (μm) 11 11 11 11 11 11 Energy density 2.8 2.82.8 2.8 2.8 2.8 (W/μm²) Laser irradiation 10000 7500 7500 10000 750010000 speed (mm/sec) Number of lines 120 120 120 80 80 80 Line distance0.05 0.05 0.05 0.05 0.05 0.05 (b1) (mm) Line group — — — — — — distance(b2) (mm) Number of times 30 10 10 30 10 10 of repetition Processingarea (mm²) 90 90 90 40 40 40 Processing time(s) 9 4 4 9 4 3 Inner space(pieces) — — — 8 6 5 Tensile joining 35 39 21 29 26 21 strength (MPa)

In Example 16, since the number of times of repetition was larger thanin Examples 7 to 9, the tensile joining strength (S2) was enhancedalthough the processing time was increased (FIGS. 28 and 29).

In Example 17 (SUS304), although as compared with example 9 (aluminum)in Table 2, the laser irradiation speed was decreased and the processingtime was increased, the tensile joining strength (S2) was increased(FIG. 30).

In Example 18 (SUS304, PP including GF), as compared with Example 17(SUS304, PA including GF), the tensile joining strength (S2) was loweredalthough the same conditions were used.

In Example 19, as compared with Examples 10 to 12 in Table 3, the numberof times of repetition was large, and thus the tensile joining strength(S2) was increased although the processing time was increased.

In Example 20 (SUS304) and Example 21 (SUS304; FIG. 31), as comparedwith Example 13 (aluminum) in Table 3, the laser irradiation speed wasdecreased and the number of times of repetition was increased, and thusthe tensile joining strength (S2) was increased although the processingtime was increased.

Example 1

In the same way as in Example 1, a relationship (FIG. 32) between theenergy density and the depth of the groove when the surface of thealuminum was irradiated with the laser and a relationship (FIG. 33)between the energy density and the width of the groove were tested.

Consequently, a clear difference was confirmed in the energy density ofapproximately 0.3 W/μm².

Examples 22 to 35

In the same way as in Examples 7 to 9 (Table 2), the entire surface (anarea size of 90 mm²) of the joint surface 12 of a metal molded body (themetal shown in Table 5) shown in FIG. 18 was continuously irradiatedwith laser light under the conditions shown in Table 5.

Thereafter, the composite molded body shown in FIG. 19 was obtained inthe same way as in Examples 1 to 6 and Comparative Examples 1 to 3.

As to the obtained composite molded body, the tensile joining strength(S2) corresponding to the Y direction (the Y direction of FIG. 20) shownin FIG. 1 was measured by the following method.

In the tensile test, as shown in FIG. 20, in a state where the side ofthe metal molded body 10 was fixed by a jig 70, when the compositemolded body was pulled in the Y direction (the Y direction of FIG. 1,the vertical direction with respect to the joint surface 12) shown inFIG. 20 until the metal molded body 10 and the resin molded body 20 werebroken, there was measured the maximum load until the joint surface 12was broken.

<Tensile Test Conditions>

Test machine: Tensilon (UCT-1T) manufactured by Orientec Co., Ltd

Tensile speed: 5 mm/min

Distance between chucks: 50 mm

TABLE 5 Examples 22 23 24 25 26 27 28 29 Type of metal SUS304 Type ofresin PA66 (including GF) Joining method Injection molding Laseroscillator Fiber laser Waveform Continuous wave Output (W) 274 274 274274 274 274 274 274 Wavelength (nm) 1070 1070 1070 1070 1070 1070 10701070 Spot diameter (μm) 12 12 30 30 30 30 11 11 Energy density 2.5 2.50.4 0.4 0.2 0.2 2.8 2.8 (W/μm²) Laser irradiation 10000 2000 10000 200010000 2000 7500 7500 speed (mm/sec) Number of lines 120 120 120 120 120120 120 120 Line distance 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 (b1)(mm) Number of times of 1 1 1 1 1 1 5 15 repetition (times) Processingarea (mm²) 90 90 90 90 90 90 90 90 Processing time(s) 0.6 3.0 0.6 3.00.6 3.0 2.0 6.0 Tensile joining 36 10 26 3 8 8 38 44 strength (MPa)Examples 30 31 32 33 34 35 Type of metal Al (A5052) Mg(AZ31) Type ofresin PA66 PA66 (including GF) (including GF) Joining method Injectionmolding Injection molding Laser oscillator Fiber laser Fiber laserWaveform Continuous wave Continuous wave Output (W) 274 274 274 274 274274 Wavelength (nm) 1070 1070 1070 1070 1070 1070 Spot diameter (μm) 1111 11 11 11 11 Energy density 2.8 2.8 2.8 2.8 2.8 2.8 (W/μm²) Laserirradiation 10000 10000 10000 10000 10000 10000 speed (mm/sec) Number oflines 120 120 120 120 120 120 Line distance 0.05 0.05 0.05 0.05 0.050.05 (b1) (mm) Number of times of 15 20 25 1 3 5 repetition (times)Processing area (mm²) 90 90 90 90 90 90 Processing time(s) 4.5 6.0 7.50.6 1.6 2.1 Tensile joining 34 38 37 4 13 26 strength (MPa)

Examples 36 to 42

In the same way as in Examples 7 to 9 (Table 2), the entire surface (anarea size of 90 mm²) of the joint surface 12 of a metal molded body (themetal shown in Table 6) shown in FIG. 18 was continuously irradiatedwith laser light under the conditions shown in Table 6.

Thereafter, the composite molded body shown in FIG. 19 was obtained inthe same way as in Examples 1 to 6 and Comparative Examples 1 to 3.

As to the obtained composite molded body, the tensile joining strength(S2) corresponding to the Y direction (the Y direction of FIG. 20) shownin FIG. 1 was measured by the following method.

In the tensile test, as shown in FIG. 20, in a state where the side ofthe metal molded body 10 was fixed by a jig 70, when the compositemolded body was pulled in the Y direction (the Y direction of FIG. 1,the vertical direction with respect to the joint surface 12) shown inFIG. 20 until the metal molded body 10 and the resin molded body 20 werebroken, there was measured the maximum load until the joint surface 12was broken.

<Tensile Test Conditions>

Test machine: Tensilon (UCT-1T) manufactured by Orientec Co., Ltd

Tensile speed: 5 mm/min

Distance between chucks: 50 mm

TABLE 6 Examples 36 37 38 39 40 41 42 Type of metal Al (A5052) Type ofresin PA66 (including GF) Joining method Injection molding Laseroscillator Fiber laser Waveform Continuous wave Output (W) 2000 20002000 2000 2000 2000 2000 Wavelength (nm) 1070 1070 1070 1070 1070 10701070 Spot diameter (μm) 21 47 47 80 80 80 80 Energy density 6.0. 1.1 1.10.4 0.4 0.4 0.4 (W/μm²) Laser irradiation 4300 10000 6000 10000 60006000 6000 speed (mm/sec) Number of lines 22 37 28 37 28 28 28 Linedistance 0.27 0.16 0.21 0.16 0.21 0.21 0.21 (b1) (mm) Number of times of1 1 1 1 1 3 10 repetition (times) Processing area (mm²) 90 90 90 90 9090 90 Processing time(s) 0.16 0.11 0.14 0.11 0.14 0.44 1.50 Tensilejoining 2 7 3 8 9 25 37 strength (MPa)

REFERENCE SIGNS LIST

-   -   1 composite molded body    -   10 metal molded body    -   12 joint surface    -   20 resin molded body

What is claimed is:
 1. A surface-roughening method for a metal moldedbody, comprising a step of roughening a surface of the metal molded bodyby continuously irradiating a joint surface of the metal molded bodywith laser light at an irradiation speed of 2,000 to 15,000 mm/sec froma continuous-wave laser, wherein the energy density (W/um²) determinedfrom the laser output and the spot area, which is π×[spot diameter/2]²,0.2 to 6.0 W/um², wherein the laser light forms a plurality of straightlines, a plurality of curved lines or lines composed of combinations ofthese, and the laser light is continuously irradiated such that theplurality of straight lines or the plurality of curved lines are formedat intervals in a range of 0.005 to 1 mm.
 2. The surface-rougheningmethod for a metal molded body according to claim 1, wherein, when thejoint surface of the metal molded body is continuously irradiated withlaser light at an irradiation speed of 2,000 to 15,000 mm/sec, the laserlight forms a plurality of straight lines, a plurality of curved linesor lines composed of combinations of these, and the laser light iscontinuously irradiated such that the plurality of straight lines or theplurality of curved lines are formed at intervals in a range of 0.005 to1 mm into one group, and a plurality of such groups are formed atintervals in a range of 0.01 to 1 mm.
 3. The surface-roughening methodfor a metal molded body according to claim 1, wherein the laser light iscontinuously irradiated such that a processing time is in a range of 0.1to 30 seconds when the area of the joint surface of the metal moldedbody is 100 mm².
 4. The surface-roughening method for a metal moldedbody according to claim 1, wherein the laser output is 250 to 2,000 W,the laser beam spot diameter is 10 to 80 μm and the energy density(W/μm²) determined from the laser output and the laser irradiation spotarea, which is π×[spot diameter/2]², is in a range of 0.2 to 6.0 W/μm².